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arXiv · 2503.09544

Quantum position verification in one shot: parallel repetition of the $f$-BB84 and $f$-routing protocols

Llorenç Escolà-Farràs·Florian Speelman
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Abstract

Quantum position verification (QPV) aims to verify an untrusted prover's location by timing communication with them. To reduce uncertainty, it is desirable for this verification to occur in a single round. However, previous protocols achieving one-round secure QPV had critical drawbacks: attackers pre-sharing an EPR pair per qubit could perfectly break them, and their security depended on quantum information traveling at the speed of light in vacuum, a major experimental challenge in quantum networks. In this work, we prove that a single round of interaction suffices for secure position verification while overcoming these limitations. We show that security for a one-round protocol can rely only on the size of the classical information rather than quantum resources, making implementation more feasible, even with a qubit error tolerance of up to 3.6%, which is experimentally achievable with current technology -- and showing that the timing constraints have to apply only to classical communication. In short, we establish parallel repetition of the $f$-BB84 and $f$-routing QPV protocols. As a consequence of our techniques, we also demonstrate an order-of-magnitude improvement in the error tolerance for the sequential repetition version of these protocols, compared to the previous bounds of Nature Physics 18, 623-626 (2022).

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Llorenç Escolà-Farràs, Florian Speelman. 2025-03-12. Quantum position verification in one shot: parallel repetition of the $f$-BB84 and $f$-routing protocols. https://arxiv.org/abs/2503.09544

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